Document how to increase request timeout when on flaky network

[demeringo]

Problem

When app or test are executed from an unreliable network, it works or not depending on network state, and edfault timeouts or retry lead to false negatives.

Solution

Set manually different retries numbers or timeout through command line.

Document this.

• Custom reties: https://docs.aws.amazon.com/sdk-for-rust/latest/dg/retries.html
• https://docs.aws.amazon.com/sdk-for-rust/latest/dg/environment-variables.html

Alternatives

Additional context or elements

[demeringo]

export AWS_MAX_ATTEMPTS=15